CEACAM5 and signet ring cell carcinoma: On multivariable logistic regression among development cohort in the risk model, rectal cancer, poorly-undifferentiation, signet-ring cell carcinoma, CEA positive, N1/N2 stages, brain metastasis, liver metastasis and lung metastasis were significantly associated with higher risk of developing BM, which were used to develop the risk model of predicting BM.